Mary Warren is an interesting character. She is timid and easily manipulated by John and Abby, but she does stand up for herself at times. Like John, Mary is constantly conflicted by the opposition of doing what's right and saving herself.

In Act 1, Mary pleads with Abby to cut the charade so they don't get into any more trouble. "Abby, we've got to tell. Witchery's a hangin' error, a hangin' like they done in Boston two years ago! We must tell the truth, Abby! You'll only be whipped for dancin', and the other things!"

In Act 2, Mary returns from the court proceedings to inform the Proctors of what has transpired. She also leaves a doll (poppet) at their house which Abby will later use to incriminate Elizabeth. "I made a gift for you today, Goody Proctor. I had to sit long hours in a chair, and passed the time with sewing." Despite Mary's attempts to come clean, she has been persuaded by Abby to engage in conspiring to incriminate Elizabeth. However, Mary does later admit to the Proctors and Hale that the poppet is hers. Following this episode, the end of Act 2, John orders Mary to go with him to court.

At the beginning of Act 3, Mary admits to the court (Danforth and others) that the girls had lied (pretense) when they accused others of "sending their spirits" against the girls.

Later in Act 3, Danforth asks Mary to pretend to faint to prove she can repeat this pretense. Mary is so bewildered she can't bring herself to do it. She provides one of the best descriptions in the play of how one (Mary) can become caught up in the hysteria/mob mentality.

It were only sport in the beginning, sir, but then the whole world cried spirits, spirits, and I--I promise, you, Mr. Danforth, I only thought I saw them but I did not.

At the conclusion of Act 3, Abby and the other girls pretend that Mary is sending her spirit on them. Terrified and desperate to save herself, Mary again is manipulated by this outburst from the girls. She shifts the blame to John Proctor. "I'll murder you," he says, "if my wife hangs! We must go and overthrow the court," he says!"

Mary is a relatively sympathetic character because John and Abigail use her like a pawn. She is at the mercy of their manipulations and therefore feels forced to bounce between truth and lies.